U.S. patent number 6,425,740 [Application Number 09/627,852] was granted by the patent office on 2002-07-30 for resonator pumping system.
This patent grant is currently assigned to SARCOS, L.C.. Invention is credited to Clark C. Davis, Stephen C. Jacobsen.
United States Patent |
6,425,740 |
Jacobsen , et al. |
July 30, 2002 |
**Please see images for:
( Certificate of Correction ) ** |
Resonator pumping system
Abstract
A resonator pump system includes a resonating structure
configured for resonating, and a fluid pump coupled to and driven
by the resonating structure. An energy source is operatively
coupled to the resonating structure for maintaining resonance.
Inventors: |
Jacobsen; Stephen C. (Salt Lake
City, UT), Davis; Clark C. (Salt Lake City, UT) |
Assignee: |
SARCOS, L.C. (Salt Lake City,
UT)
|
Family
ID: |
24516405 |
Appl.
No.: |
09/627,852 |
Filed: |
July 28, 2000 |
Current U.S.
Class: |
417/2;
417/415 |
Current CPC
Class: |
F04B
7/0076 (20130101); F04B 17/003 (20130101); F04B
17/042 (20130101); F04B 19/006 (20130101) |
Current International
Class: |
F04B
7/00 (20060101); F04B 17/04 (20060101); F04B
17/00 (20060101); F04B 17/03 (20060101); F04B
19/00 (20060101); F04B 041/06 () |
Field of
Search: |
;417/415,416,501,490,244,413.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Freay; Charles G.
Assistant Examiner: Rodriguez; William H.
Attorney, Agent or Firm: Thorpe North & Western
Claims
What is claimed is:
1. A resonator pump system comprising: a resonating structure
configured for resonating movement; an energy source operatively
coupled to the resonating structure for maintaining resonance; and
a fluid pump coupled to and driven by the resonating structure.
2. The resonator pump system of claim 1, wherein the resonating
structure resonates between approximately 200 Hz to 2 KHz.
3. The resonator pump system of claim 1 wherein the fluid pump has
a diameter between approximately 100 to 1000 microns.
4. The resonator pump system of claim 1, wherein the resonating
structure has a mass substantially greater than a mass of fluid in
the fluid pump.
5. The resonator pump system of claim 1, wherein the resonating
structure has kinetic energy substantially greater than an amount
of energy used to drive the fluid pump.
6. The resonator pump system of claim 1, wherein the resonating
structure resonates at a constant amplitude.
7. The resonator pump system of claim 1, wherein the resonating
structure resonates at a constant frequency.
8. The resonator pump system of claim 1, further comprising: a
sensor configured for sensing the resonation of the resonating
structure and producing a sensor signal; and wherein the energy
source includes a driver responsive to the sensor signal for
applying a force to the resonating structure to maintain the
resonance.
9. The resonator pump system of claim 8, further comprising: a
controller coupled to the driver and the sensor for controlling the
amplitude or frequency of the resonating structure.
10. The resonator pump system of claim 1, wherein the energy source
is a magnet.
11. The resonator pump system of claim 1, wherein the fluid pump is
mechanically coupled to a moving portion of the resonating
structure by a transmission arm coupled to and between the
resonating structure and the fluid pump.
12. The resonator pump system of claim 1, wherein the fluid pump is
coupled to the resonating structure by a flexible arm rigidly
coupled to both the pump and the structure.
13. The resonator pump system of claim 1, wherein the fluid pump is
coupled to the resonating structure by a rigid arm pivotally
coupled to both the pump and the structure.
14. The resonator pump system of claim 1, wherein the resonating
structure includes: a base; a spring element coupled at one end to
the base; and a mass, coupled to another end of the spring element,
and configured for linear motion with respect to the base.
15. The resonator pump system of claim 1, wherein the resonating
structure includes: a base; an elongated and flexible spring
element with one end coupled to the base; and a mass, coupled to
another end of the flexible spring element, and configured for
arcuate motion with respect to the base.
16. The resonator pump system of claim 1, wherein the resonating
structure includes: a base; and a piezoelectric element, coupled to
the base, and configured for bending under an applied electric
field.
17. The resonator pump system of claim 1, wherein the fluid pump
includes: a cavity having a fluid inlet and a fluid outlet; and a
piston, movably disposed within the cavity and operatively coupled
to the resonating structure.
18. The resonator pump system of claim 1, wherein the fluid pump
comprises first and second fluid pumps including: a first cavity
disposed on one side of the resonating structure; and a first
piston, movably disposed within the first cavity and operatively
coupled to the resonating structure; and a second cavity disposed
on another side of the resonating structure; and a second piston,
movably disposed within the second cavity and operatively coupled
to the resonating structure, such that the first and second fluid
pumps alternately pump to achieve a substantially constant fluid
flow.
19. The resonator pump system of claim 1, wherein the resonating
structure includes: an elongated and flexible spring element with
one end coupled to a base; and a mass, coupled to another end of
the flexible spring element, and configured for arcuate motion;
and
wherein the fluid pump includes: a cavity disposed proximate the
spring element; and a piston directly connected to the spring
element.
20. The resonator pump system of claim 1, wherein the fluid pump
further includes a fluid inlet and a fluid outlet, each having a
valve selected from the group consisting of duckbill check valves,
ball check valves, and spool valves.
21. The resonator pump system of claim 1, further comprising: a
spool valve fluidly coupled to the fluid pump; and a second
resonating structure, coupled to the spool valve, and configured
for resonating 90 degrees out of phase from the first resonating
structure.
22. The resonator pump system of claim 1, further comprising: a
plurality of resonating structures coupled to a plurality of fluid
pumps, the fluid pumps being coupled in series to increase
pressure.
23. The resonator pump system of claim 1, further comprising: a
plurality of resonating structures coupled to a plurality of fluid
pumps, the fluid pumps being coupled in parallel to increase
flow.
24. The resonator pump system of claim 1, further comprising: a
first plurality of resonating structures coupled to a first
plurality of fluid pumps, the first plurality of fluid pumps being
coupled in series to increase pressure; and a second plurality of
resonating structures coupled to a second plurality of fluid pumps,
the second plurality of fluid pumps being coupled in parallel to
increase flow.
25. The resonator pump system of claim 24, wherein the plurality of
resonating structures and fluid pumps are individually operable to
control the pressure and flow.
26. The resonator pump system of claim 1, wherein both the
resonating structure and fluid pump comprise: first and second flat
layers; and a third layer, sandwiched between the first and second
layers, and being patterned with openings to form both the
resonating structure and the fluid pump.
27. The resonator pump system of claim 1, wherein the fluid pump
and resonating structure are inserted into an IV line.
28. A resonator pump system comprising: a resonating structure
including a resonating mass configured for oscillating motion, and
an energy storing and releasing system coupled-to the resonating
mass; an energy source, coupled to the resonating structure, for
maintaining the oscillating motion of the mass; a transmission arm,
coupled to a moving portion of the resonating structure, for
coupling the oscillating motion of the resonating mass; a fluid
pump, driven by the resonating structure, and including a cavity
and a piston movably disposed in the cavity and operatively coupled
to the transmission arm.
29. A resonator pump system comprising: a resonating structure
configured for oscillating motion; a driver, operatively engaging
the resonating structure, for applying a force to the resonating
structure to maintain the oscillating motion; a transmission arm
operatively coupled to a moving portion of the reciprocating
structure; a cavity having a fluid inlet and a fluid outlet; and a
piston, movably disposed within the cavity and operatively coupled
to the transmission arm.
30. A resonator pump system comprising: first and second layers; a
third layer, sandwiched between the first and second layers, and
patterned with openings to form: a resonating structure, attached
to the third layer, and configured for resonating; a fluid pump
including a cavity and a piston movably disposed in the cavity; and
a transmission arm coupled to and extending between the resonating
structure and the piston.
31. A resonator pump system comprising: a first resonating
structure configured for resonating; a fluid pump coupled to and
driven by the first resonating structure; a second resonating
structure configured for resonating 90 degrees out of phase from
the first resonating structure; a spool valve, fluidly coupled to
the fluid pump, and operatively coupled to and driven by the second
resonating structure; and at least one an energy source operatively
coupled to the resonating structures for maintaining resonance.
Description
BACKGROUND OF THE INVENTION
1. The Field of the Invention
The present invention relates generally to a resonator pumping
system, particularly useful as an accurate drug delivery system,
and having a resonating structure coupled to a fluid pump for
pumping fluid.
2. The Background Art
Many applications or situations require accurately pumping or
metering relatively small quantities of fluid. For example, IV
pumps have been developed to accurately meter or control medicament
from an IV bladder to an IV needle for treating a patient. The
intravenous administration of fluids to patients is a well-known
medical procedure for, among other things, (i) providing life
sustaining nutrients to patients whose digestive tracts are unable
to function normally due to illness or injury, (ii) supplying
antibiotics to treat a variety of serious infections, (iii)
delivering analgesic drugs to patients suffering from acute or
chronic pain, (iv) administering chemotherapy drugs to treat
patients suffering from cancer, etc.
The intravenous administration of drugs frequently requires the use
of an IV pump connected or built into a so-called IV administration
set including, for example, a bottle of fluid to be administered
and typically positioned upside down, a sterile plastic tubing set,
and a pump for pumping fluid from the bottle through the IV set to
the patient. Other mechanisms may be included to manually stop the
flow of fluid to the IV feeding tube and possibly some monitoring
devices.
Current IV pumps generally are of two basic types: electronic pumps
and disposable non-electronic pumps. Although the electronic pumps
have been significantly miniaturized and do include some disposable
components, they are nevertheless generally high in cost, require
frequent maintenance with continued use, and may be difficult for a
layman to operate if, for example, self treatment is desired.
The disposable non-electric pumps generally consist of small
elastomeric bags within a hard shell container, in which the bags
are filled with IV solution under pressure. The pressure generated
by the contraction of the elastomeric bag forces the IV solution
through a fixed orifice at a constant flow rate into the patient's
vein. Although these pumps are much less expensive than the
electronic pumps and eliminate the need for maintenance (since they
are discarded after every use), their drawbacks include the lack of
monitoring capability, the lack of the ability to select different
flow rates, limited fluid capacity, and still relatively high cost
for a disposable product.
Disadvantages with many prior art IV pumps includes their
relatively large size, complexity, and cost. Such IV pumps are
typically bulky, complicated, and costly to produce and use.
OBJECTS AND SUMMARY OF THE INVENTION
It has been recognized that it would be advantageous to provide a
pump system which would allow precise pumping or metering of
fluids, such as medicament, including IV fluids, and other
application where the fluid is more concentrated, such as insulin,
PCA, and chemotherapy. In addition, it has been recognized that it
would be advantageous to provide such a pump system which is cost
effective to produce and use, and which may be disposable. In
addition, it has been recognized that it would be advantageous to
provide such a pump system which is small and controllable.
The invention provides a resonator pump system including a
resonating structure configured for resonating, and a fluid pump
coupled to and driven by the resonating structure. The fluid pump
preferably includes a cavity having a fluid inlet and a fluid
outlet, and a piston movably disposed within the cavity and
operatively coupled to the resonating structure. An energy source
is operatively coupled to the resonating structure for maintaining
resonant reciprocation.
In accordance with one aspect of the present invention, the
resonating structure reciprocates at a relatively high frequency,
such as between 200 Hz to 2 Khz, and the fluid pump is relatively
small, having a cavity or piston diameter of between 100 to 1000
microns.
In accordance with another aspect of the present invention, the
pump system includes a sensor for sensing the resonation of the
resonating structure and producing a sensor signal. The energy
source may include a driver which is responsive to the sensor
signal for applying a force to the resonating structure to maintain
the resonance. A controller may be coupled to the driver and the
sensor for controlling the amplitude or frequency of the resonating
structure.
In accordance with another aspect of the present invention, the
fluid pump is mechanically coupled to a moving portion of the
resonating structure by a transmission arm coupled to and between
the resonating structure and the fluid pump. The transmission arm
may be a flexible arm rigidly coupled to both the pump and the
structure. Alternatively, the transmission arm may be a rigid arm
pivotally coupled to both the pump and the structure.
In accordance with one embodiment of the present invention, the
resonating structure includes a spring element coupled to a mass,
and configured for linear motion with respect to the base.
In accordance with another embodiment of the present invention, the
resonating structure includes an elongated and flexible spring
element coupled to a mass, and configured for arcuate motion with
respect to the base.
In accordance with another embodiment of the present invention, the
resonating structure includes a piezoelectric element configured
for bending under an applied electric field.
In accordance with another embodiment of the present invention, the
fluid pump comprises first and second fluid pumps on opposite sides
of the resonating structure to achieve a substantially constant
fluid flow.
In accordance with another embodiment of the present invention, the
fluid pump includes a cavity disposed proximate the spring element,
and a piston directly connected to the spring element.
In accordance with another embodiment of the present invention, the
system includes a spool valve fluidly coupled to the fluid pump,
and a second resonating structure coupled to the spool valve, and
configured for resonating 90 degrees out of phase from the first
resonating structure.
In accordance with another aspect of the present invention, a
plurality of resonating structures are coupled to a plurality of
fluid pumps with the fluid pumps being coupled in series to
increase pressure. In addition, fluid pumps may be coupled in
parallel to increase flow.
In accordance with another embodiment of the present invention, the
system may include first and second flat layers, and a third layer
sandwiched between the first and second layers. The third layer is
patterned with openings to form both the resonating structure and
the fluid pump.
The fluid pump and resonating structure may be inserted into an IV
line in order to pump or meter medicament to an IV needle.
Additional objects and advantages of the invention will be set
forth in the description which follows, and in part will be
apparent from the description, or may be learned by the practice of
the invention without undue experimentation. The objects and
advantages of the invention may be realized and obtained by means
of the instruments and combinations particularly pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the
invention will become apparent from a consideration of the
subsequent detailed description presented in connection with the
accompanying drawings in which:
FIG. 1 is a schematic view of a first presently preferred
embodiment of a resonator pump system in accordance with the
present invention;
FIG. 2 is a schematic view of a second presently preferred
embodiment of a resonator pump system of the present invention;
FIG. 3 is a schematic view of a third presently preferred
embodiment of a resonator pump system of the present invention;
FIG. 4 is a schematic view of a fourth presently preferred
embodiment of a resonator pump system of the present invention;
FIG. 5 is a schematic view of a fifth presently preferred
embodiment of a resonator pump system of the present invention;
FIGS. 6a and 6b are schematic views of a sixth presently preferred
embodiment of a resonator pump system of the present invention;
and
FIGS. 7 and 8 are schematic views of a seventh presently preferred
embodiment of a resonator pump system of the present invention.
DETAILED DESCRIPTION
For the purposes of promoting an understanding of the principles in
accordance with the invention, reference will now be made to the
embodiments illustrated in the drawings and specific language will
be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended. Any alterations and further modifications of the
inventive features illustrated herein, and any additional
applications of the principles of the invention as illustrated
herein, which would normally occur to one skilled in the relevant
art and having possession of this disclosure, are to be considered
within the scope of the invention claimed.
As illustrated in FIGS. 1-8, various presently preferred
embodiments of resonator pumping systems are shown in accordance
with the present invention for pumping a fluid. The systems
generally include a resonating structure 14 coupled to a fluid pump
18, which may take various different forms, as described in greater
detail below. The resonating structure 14 may include a mass and
spring element which alternate between kinetic and potential energy
states, or between maximum and minimum kinetic and potential
energies. Such resonating structures 14 may resonate or oscillate
for extended periods of time, or continuously without any losses,
such as friction.
Referring to FIG. 1, a first presently preferred embodiment of a
resonator pump system, indicated generally at 10, is shown for
pumping a fluid, such as a medicament, from a fluid reservoir or
bladder 22, to a desired location, such as an IV needle 26. Thus,
the resonator pumping systems maybe utilized to accurately pump or
meter medicament, such as insulin for diabetics; chemotherapy
fluids; etc.
The resonating structure 14 includes a moving body, member, or
element 30 having a mass m. The resonating structure 14 or body 30
resonates or oscillates back and forth, as indicated by arrow 34,
along a linear movement path. The resonating structure 14 also
includes an energy storing and releasing system, such as a
compression spring 38. The spring 38 compresses and extends to
store and release energy. Thus, the body or mass 30, and spring 38,
form the resonating structure 14 and resonate or oscillate 34. As
the resonating structure 14 oscillates back and forth in a linear
fashion, it moves from a position of greatest potential energy (and
least kinetic energy) at the far left range of motion, through a
position of greatest kinetic energy (and least potential energy) as
it moves through its middle range of motion, to a position of
greatest potential energy (and least kinetic energy) at the far
right range of motion.
The fluid pump 18 may be a piston pump and include a cavity or tube
42, and a piston 46 slidably disposed within the cavity. The piston
46 moves back and forth in the cavity 42 to vary the volume or
capacity of the cavity 42.
The cavity 42 includes a fluid inlet for allowing fluid into the
cavity 42, and a fluid outlet for allowing fluid to exit the cavity
42. Inlet and outlet check valves 50 and 52 are located at the
respective fluid inlet and outlet. Thus, the inlet check valve 50
allows unidirectional flow into the cavity 42 from the fluid
reservoir 22, while preventing fluid flow back into the reservoir
22. Similarly, the outlet check valve 52 allows unidirectional flow
out of the cavity 42 to the needle 26, while preventing fluid flow
back into the cavity 42.
As the piston 46 moves out of the cavity 42, a vacuum (or pressure
differential) is created which draws fluid through the inlet check
valve 50 and into the cavity 42. As the piston 46 moves into the
cavity 42, the piston 46 pushes (or again creates a pressure
differential) which forces the fluid through the outlet check valve
52 and into the needle 26.
The fluid pump 18 or piston 46 is advantageously operatively
coupled to the resonating structure 18. A transmission arm 56 is
coupled to and extends between a moving portion of the resonating
structure 14, or body 30, and the piston 46 of the pump 18. Thus,
the oscillatory motion of the resonating structure 14 is
transferred to the piston 46 to drive the pump 18.
As indicated above, resonating structures may resonate or oscillate
for extended periods of time, or continually without losses. Such
resonating structures typically experience losses, such as
friction, which eventually cause the resonating structure to stop
resonating. Thus, an energy source, indicated generally at 60, is
operative coupled to the resonating structure 14 for maintaining
the resonance, or oscillatory motion. The energy source 60 may
include a driver 64, such as an electromagnet, which exerts a force
on the resonating structure 14, of body 30.
In addition, a sensor 68 may be positioned to sense the resonation
or oscillatory motion of the resonating structure 18 or body 30 and
produce a sensor signal. A controller 72 is coupled to the driver
64 and is responsive to the sensor signal for controlling the
driver 64, and thus maintaining or controlling the amplitude and
frequency of the resonation.
Referring to FIG. 2, a second presently preferred embodiment of a
resonator pump system, indicated generally at 80, has a resonating
structure 14 which also includes a moving body, member, or element
84 having a mass m. The resonating structure 14 or body 84
resonates or oscillates back and forth, as indicated by arrow 88,
along an arcuate movement path. The resonating structure 14 also
includes an energy storing and releasing system, such as a
cantilever spring or elongated flexible member 92. The spring 92 is
flexible and bends back and forth to store and release energy.
Thus, the mass 84 is disposed on an end of the cantilever spring 92
to form the resonating structure 14. As the resonating structure 14
oscillates back and forth in an arcuate fashion, it moves from a
position of greatest potential energy (and least kinetic energy) at
the far left range of motion (shown in dashed lines), through a
position of greatest kinetic energy (and least potential energy) as
it moves through its middle range of motion (shown in dashed
lines), to a position of greatest potential energy (and least
kinetic energy) at the far right range of motion.
Again, an energy source or driver 94, such as an electromagnet, may
maintain the resonance of the resonating structure 14, or body 84
and spring 92 Coils 95 may be formed in the body 84 which are acted
upon by the magnet, which is held stationary. Alternatively, the
magnet may be located in the body, and the coils 64 held
stationary. As stated above, a controller 72 can be coupled to the
driver 64 or coils 95 to maintain the resonation and/or control the
amplitude and frequency of the resonation.
The fluid pump 18 may be similar to the piston pump described
above. The fluid pump 18 may include check valves 96, such as ball
valves, as shown.
In addition, the piston 46 is coupled to the resonating structure
18, or cantilever spring 92, by a flexible transmission arm 100
rigidly attached to the piston 46 and spring 92, as described in
greater detail below.
Referring to FIG. 3, a third presently preferred embodiment of a
resonator pump system, indicated generally at 110, has a resonating
structure 14 which includes a piezoelectric element 114. The
resonating structure 14 or piezoelectric element 114 resonates or
oscillates back and forth, as indicated by arrow 118, along an
arcuate movement path. The resonating structure 14 or piezoelectric
element 114 has layers of material which bend or flex under an
applied electric field. The piezoelectric element 114 may be
configured to be straight in a natural, un-flexed state, and bend
under the applied electric field, such that energy is stored in the
bent element 114. Alternatively, the element 114 may be configured
to be curved in a natural, un-flexed state, and bend to a straight
configuration, or oppositely curved configuration, under the
applied electric field. Electrical contacts 122 are coupled to the
piezoelectric element 114 for applying an electric field.
The fluid pump 18 may be similar to the piston pump described
above. The fluid pump 18 may include check valves 126, such as
duckbill valves, as shown.
In addition, the piston 46 is coupled to the resonating structure
18, or piezoelectric element 114, by a rigid transmission arm 130
pivotally attached to the piston 46 and resonating structure 14, as
described in greater detail below.
Referring to FIGS. 2 and 3, the fluid pumps 18, or pistons 46, are
coupled to the resonating structures 14 by transmission arms 100
(FIG. 2) and 130 (FIG. 3). Referring to FIG. 2, the transmission
arm 100 is flexible and rigidly connected to both the piston 46 and
the resonating structure 14. Because the resonating structure 14
moves in an arcuate fashion and the arm 100 is rigidly coupled, the
flexibility of the arm 100 allows the arm to bend as the resonating
structure 14 moves, as indicated by the dashed lines. Thus, as the
connection points between the arm 100 and the piston 46 and
resonating structure 14 move, the arm 100 bends rather than
pivoting about the connection points. The flexible arm 100 may be a
thin filament, which may be integrally formed with the piston or
cantilever spring, and thus may be more inexpensive to produce.
Referring to FIG. 3, the transmission arm 130 is rigid and
pivotally or flexibly connected to both the piston 46 and the
resonating structure 14. As the resonating structure 14 moves along
the arcuate path, the arm 130 pivots with respect to the piston 46
and resonating structure 14 about its connections. The arm 130 may
be pivotally connected by pivot joints. The pivotal joints may
present less resistance, and thus present less losses.
Referring to FIG. 4, a fourth presently preferred embodiment of a
resonator pump system, indicated generally at 140, has a resonating
structure 14 similar to the mass 84 and cantilever spring 92
discussed above. In addition, the fluid pump 18 may be a piston
pump with a piston 144 directly connected to the resonating
structure 14 or cantilever spring 92, and extending therefrom in
both directions of travel. Furthermore, the fluid pump 18 has
cavities 148 and 150 disposed on both sides of the resonating
structure 14. The piston 144 has a first portion which extends in
one direction into the first cavity 148, and a second portion which
extends in the opposite direction into the second cavity 150.
The piston sides and cavities form two pump halves such that the
system 140 continually pumps as the resonating structure 14
resonates. As the resonating structure 14 displaces to the right,
the first piston portion withdraws from the first cavity 148,
drawing fluid into the first cavity 148, while the second piston
portion simultaneously forces fluid from the second cavity 150.
Similarly, as the resonating structure displaces in the opposite
direction, the first piston portion forces fluid from the first
cavity 148, while the second piston portion simultaneously draws
fluid into the second cavity 150. Thus, the pump system 140
provides a more continuous stream of fluid, or more constant fluid
flow.
In addition, the piston 144 and cavities 148 and 150 are arcuate,
or have an arcuate cross-section. Thus, the arcuate piston 144 and
cavities 148 and 150 conform to the arcuate motion of the
resonation structure.
Referring to FIG. 5, a fifth presently preferred embodiment of a
resonator pump system, indicated generally at 160, has a resonating
structure 14 similar to the mass 84 and cantilever spring 92
discussed above, and a fluid pump 18 with cavities 164 and 166
disposed on both sides of the resonating structure 14. Similarly, a
piston 168 is directly connected to the resonating structure 14 or
spring 92. The piston 168 and cavities 164 and 166, however, are
straight, rather than arcuate. Thus, the piston 168 also is
slidably connected to the resonating structure 14 or spring 92 so
that the piston 168 slides along a connection point with the spring
92 as the spring 92 move through an arcuate movement path.
Referring to FIGS. 6a and 6b, a sixth presently preferred
embodiment of a resonator pump system, indicated generally at 180,
is shown with a spool valve 184 which also is driven by a second
resonating structure 188. Similar to the systems described above,
the system 180 has pump 190 with a cavity 192 and a piston 46, and
a resonating structure 14 with a mass 84 and a cantilever spring
92. The pump 190 may have a single inlet/outlet opening.
The spool valve 184 is fluidly coupled to the pump 190 with an
inlet/outlet opening coupled to the inlet/outlet opening of the
pump 190. The spool valve 184 also has a fluid inlet and a fluid
outlet. A spool or bobbin 196 is slidably disposed in a cavity in
the spool valve 184, and reciprocates back and forth. The spool or
bobbin 196 has a fluid passage 200 therein which extends between
the inlet/outlet opening, and either the fluid inlet or the fluid
outlet. When the spool 196 is located in a first or left position,
the fluid passage 200 extends between the inlet/outlet of the pump
190 and valve 184, and the fluid inlet, so that fluid may flow in
through the fluid inlet of the valve 184, through the fluid passage
200, through the inlet/outlet openings, and into the cavity 192 of
the pump, as shown in FIG. 6a. When the spool 196 is in a second or
right position, the fluid passage 200 of the spool 196 extends
between the inlet/outlet opening of the pump 190 and valve 184, and
the fluid outlet, so that fluid may flow out of the cavity 192 of
the pump 190, through the inlet/outlet openings, through the fluid
passage 200, and out of the fluid outlet.
The piston 46 of the fluid pump 190 is connected by a transmission
arm 204 to the first resonating structure 14. Similarly, the spool
196 of the spool valve 184 is connected by a second transmission
arm 208 to the second resonating structure 188. The second
resonating structure 188 may include a second mass 212 and a second
cantilever spring 216. The second resonating structure 188
resonates much like the first resonating structure 14, but 90
degrees out of phase from the first resonating structure 14. Thus,
the second resonating structure 188 drives or controls the spool
valve 184 to allow fluid into the pump 190 as the piston 46 is
withdrawn from the cavity 192 by the first resonating structure 14,
as shown in FIG. 6a, but displaces the spool 196 to allow fluid out
of the pump 190 as the piston 46 drives fluid from the cavity 192,
as shown in FIG. 6b.
It should be noted that the resonator pump systems described above
are intended to be relatively small, and resonate relatively
quickly, or at a relatively high frequency. For example, the
diameter of the piston or cavity may be between approximately 100
and 1000 .mu.m (microns), while the resonating structures resonate
at a frequency between approximately 200 Hz and 2 KHz. Thus,
although the fluid pumps may be relatively small, they are operated
at a relatively high frequency to obtain an appreciable flow rate,
or a flow rate suitable for certain applications, such as drug
pumping or metering.
In addition, it should be noted that the mass or energy of the
resonating structure is significantly greater than the mass of
fluid in the fluid pump, or the energy required by the fluid pump.
Thus, the fluid pump draws a relatively small amount of energy from
the resonating structure so that the resonating structure continues
to resonate.
It is anticipated that a relatively small pumping unit may be
produced which is small enough to be inserted into an IV line; have
sufficient flow rate and pressure performance to pump or meter
medicaments; and be inexpensively produced to be disposable. For
example, a small pumping unit may be inserted into an IV line and
have a small resonating structure; a driver to maintain resonance;
a battery to power the driver; a controller or microprocessor to
control the driver, and thus the resonance and flow rate; a small
piston and cavity; and appropriate check valves.
The resonating structure of the present invention may be operated
at a constant amplitude and frequency. Such a configuration
requires less complicated control, and may be more inexpensive to
produce. Alternatively, the controller 72, as discussed in FIG. 1,
may be utilized to alter the force exerted by the driver 60, in
turn altering the frequency or amplitude of the resonating
structure, and thus the flow rate of the fluid pump. Such a
configuration allows more control of the pump.
Referring now to FIGS. 7 and 8, the resonator pump system of the
present invention may be micro-fabricated, or lithographed into
layers of material, to form one or more pumps and/or resonating
structures. Thus, the resonator pump system may include one, or a
plurality of pump systems, disposed in an array or matrix. Several
pump systems, indicated by the dashed boxes 220 in FIG. 7, may be
formed by the layers. Several pump systems 220 may be disposed in
series, indicated by dashed boxes 220, 222 and 224, to increase
pressure. In addition, several pump systems 220 may be disposed in
parallel, indicated by dashed boxes 220, 226 and 228, to increase
flow rate. Additionally, several pump systems may be disposed in
series and parallel, and independently controlled, to obtain the
desired fluid flow characteristics, or rate and pressure.
The pump systems may include first and second layers 232 and 236
sandwiching a third layer 240. Referring to FIG. 8, the third layer
240 may be patterned with openings, indicated generally at 244, to
form a fluid pump 248 and resonating structure 252. In addition,
the third layer 240 may be patterned to form fluid passageways or
channels 256. Each pump 248 and resonating structure 252 form a
pump system 220. As shown in FIG. 7, a number of pump systems 220
may be patterned into the third layer 240, and sandwiched between
the first and second layers 232 and 236, to form the cavity of the
pump 248 (FIG. 8) and fluid passageways 256 (FIG. 8). Such a system
may be utilized to control the flow characteristics, such as flow
rate and pressure.
Additional layers of electrically conductive material may be
patterned on the layers in order to apply an electrical field to
the resonant structure 252 of the third layer 240.
Although the fluid pumps and resonating structures described above
have been illustrated and described as being mechanically coupled
by transmission arms, it will be appreciated that the coupling may
be accomplished by any appropriate means, including for example,
magnetically, etc.
Similarly, although the resonating structures have been described
as being operatively engaged by magnetic drivers, it will be
appreciated that the resonance of the resonating structures may be
maintained by any appropriate means, including for example,
mechanical engagement, etc.
The pump systems described above physically remove energy from a
mechanically resonating structure in order to pump a fluid.
It is to be understood that the above-described arrangements are
only illustrative of the application of the principles of the
present invention. Numerous modifications and alternative
arrangements may be devised by those skilled in the art without
departing from the spirit and scope of the present invention and
the appended claims are intended to cover such modifications and
arrangements. Thus, while the present invention has been shown in
the drawings and fully described above with particularity and
detail in connection with what is presently deemed to be the most
practical and preferred embodiment(s) of the invention, it will be
apparent to those of ordinary skill in the art that numerous
modifications, including, but not limited to, variations in size,
materials, shape, form, function and manner of operation, assembly
and use may be made without departing from the principles and
concepts set forth herein.
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